UUID v4 generator
Creates random version 4 UUIDs, one at a time or as a list of up to 500.
Runs in your browser. Nothing you enter is sent to our server.
About this tool
A UUID is a 128-bit identifier such as 3f2b8c1e-9d4a-4c7e-8b1f-2a6d5e9c0f13. Version 4 is almost entirely random bits, so it can be generated anywhere without coordination: in a database, on the client or in tests.
The generator uses crypto.randomUUID or crypto.getRandomValues — the browser’s cryptographically secure randomness — never Math.random. IDs are created on your device.
How to use
- Set how many you need, from 1 to 500.
- Optionally switch to uppercase or remove hyphens.
- Click “Generate” and copy one UUID or the whole list.
Examples
How many: 1
7c9e6679-7425-40de-944b-e07fc1f90ae7 (format example)
No hyphens, uppercase
7C9E6679742540DE944BE07FC1F90AE7
Frequently asked questions
Can two UUID v4 values collide?
In theory yes, in practice no: there are 122 random bits. You would need about 2.7 × 10¹⁸ IDs for a 50% chance of a single collision.
What is the difference between a UUID and a GUID?
None. GUID is the name used in the Microsoft ecosystem.
Should I use UUID v4 as a primary key?
You can, but random ordering hurts index performance on large tables. For time-ordered keys consider UUID v7.